SoftBank will buy the shares via a tender offer at 360 yen per share, equivalent to Monday's close. Altaba, SoftBank and Yahoo Japan agree to the deal, the companies said in separate statements.

Yahoo Japan will then buy back 220 billion of stock from SoftBank. After the transactions, the stake held by SoftBank Group and its units will rise to 48.17 percent from 42.95 percent now, and Altaba will have about 27 percent, they said.